This shared instrumentation application is for an AB Sciex Triple Quad 4500 triple quadrupole mass spectrometer as replacement for an outdated shared liquid chromatography-mass spectrometry instrument. Major research efforts at the University of Tennessee Health Science Center Colleges of Pharmacy and Medicine are directed towards the development of new molecular entities for unmet medical needs. The requested instruments supports 9 investigators with 14 research projects (10 NIH-supported) focused on small molecule drug discovery and development. Targeted indications include the treatments of a variety of cancer types, tuberculosis, radiation injury, and other conditions. Crucial assessments in early drug discovery and lead optimization include the investigation of the lead compounds' chemical and metabolic stability, biopharmaceutical and pharmacokinetic properties. The requested instrument will be utilized for the quantification of small molecule drug candidates in biologic matrices in support of these studies. Due to its high sensitivity compared to other LC-MS/MS equipment, it will allow the reliable quantification of the usually low pharmacologically active concentrations of highly potent drug candidates.